Arch Linux Security Advisory ASA-201803-5

Severity: Medium
Date : 2018-03-06
CVE-ID : CVE-2018-7536 CVE-2018-7537
Package : python-django
Type : denial of service
Remote : Yes
Link : https://security.archlinux.org/AVG-649

Summary

The package python-django before version 1.11.11-1 is vulnerable to
denial of service.

Resolution

Upgrade to 1.11.11-1.

pacman -Syu “python-django>=1.11.11-1”

The problems have been fixed upstream in version 1.11.11.

Workaround

None.

Description

• CVE-2018-7536 (denial of service)

The django.utils.html.urlize() function was extremely slow to evaluate
certain inputs due to catastrophic backtracking vulnerabilities in two
regular expressions. The urlize() function is used to implement the
urlize and urlizetrunc template filters, which were thus vulnerable.
The problematic regular expressions are replaced with parsing logic
that behaves similarly.

• CVE-2018-7537 (denial of service)

If django.utils.text.Truncator’s chars() and words() methods were
passed the html=True argument, they were extremely slow to evaluate
certain inputs due to a catastrophic backtracking vulnerability in a
regular expression. The chars() and words() methods are used to
implement the truncatechars_html and truncatewords_html template
filters, which were thus vulnerable.

Impact

A remote attacker is able to crash the application by providing
specially crafted input.

References

https://docs.djangoproject.com/en/dev/releases/1.11.11/
https://github.com/django/django/commit/8618271caa0b09daba39ff3b46567d33ae1e1d3a
https://github.com/django/django/commit/97b7dd59bb8d6163239061e2022153c3415d146d
https://security.archlinux.org/CVE-2018-7536
https://security.archlinux.org/CVE-2018-7537